Method of making printing-plate blanks and product thereof



May 1, 1923.'

1,453,384 J. s. DUNCAN METHOD OF MAKING PRINTING PLATE BLANKS ANDPRODUCT THEREOF Filed March 15 1922 Patented May 1, 1923.

JOSEPH S. DUNCAN, OIE CHICAGO, ILLINOIS.

METHOD OF MAKING PRINTING-PLATE BLANKS AND' PRODUCT THEREOF.

Application filed March 13,1922. Serial No. 543,161.

T all whom it may concern: 7

Be it known that I, JOSEPH S. DUNCAN, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Methods of MakingPrinting-Plate Blanks and Product Thereof, of which the following is aspecification. This invention relates to printing plates of that kindwhich comprises a thin metal plate having type characters stamped inrelief thereon. Such plates are prepared from blanks which are cut fromsheets or strips. The type characters are stamped in relief on the blankplates in suitable machines which operate to stamp the characters to astandard and uniform height. But some difficulty in'manufacture hasresulted from variations in the thickness of the strip or sheet andconsequently in the blanks and since the type characters are of astandard and uniform height on, every blank it may result that theimpression taken from a printing plate made from .a blank of less thanthe predetermined thickness will be too light or indistinct; or anequally unsatisfactory impression may result from a printing plate madefrom a blank which varies in thickness from end to end or from side edgeto side edge.

Since it seems to be impossible to obtain strips or sheets of a standarduniform thickness I have found it necessary to process the blanks sothat the printing face of the type characters of every plate will alwaysbe in a plane parallel with and uniformly spaced from the plane of theback supporting face of the plate and thus insure a uniform impressionof predetermined character from all printing plates. 7

This being the broad and fundamental object of the invention, I also aimto accomplish the aforesaid desirable results in a simple and effectivemanner which will not involve any changein the present method and meansof cutting the blanks, stamping the characters thereon, or using theprinting'plates.

In the accompanying drawings illustrating a selected embodiment of theinvention produced by a method which. I have found to be satisfactory inpractice Fig. 1 is a plan View of one form of blank which may be usedand Fig. 2 is a side view of the same blank; I Fig. 3 is a plan viewshowing the back of the blank with projections thereon and. Fig. 4 is anedge view of thesame blank;

Fig. 5 is a diagrammatic view showing a pair of rolls with the blanks ofFigs.o3 and at passed part way therethrough; I Fig. 6 is an end view ofone plate and Fig. 7 is an edge view, of another' plate, both embodyingmy invention and showing it meeting different conditions. 5 Referring tothe drawings, 8 designates a blank which may be of any suitable formdiffering from that shown, and which is adapted 'to receive typecharacters 9 stamped in relief thereon in a suitable machine. This 7blank is cut from a strip or sheet. of metal which will have a gauge orthickness as uniformly standard as present commercial manufactureproduces but which, in fact is known to vary more or less in thickness.,Itwill be understood, of course, that if the blank departs too far froma predetermined standard and exceeds predetermined limits it will berejected as unfit for making a. printing plate even with the presentinvention; but if the blank departs from the standard thickness andvaries only within certain predetermined limits it can be usedsatisfactorily in the production of a printing plate according'topresent methods provided it is first processed in accordance with. myinvention. The predetermined limits referred to will depend upon thecharacter of the metal, the height and character of the type charactersto be stamped and other conditions which will be apparent to thoseskilled in the art, and since these limits may vary with the conditionsI will not attempt to specify any particular limits. The blank 8 isstamped to provide a plu- 95 rality of projections 10 on the backthereof. These project-ions may vary in size, shape, location andarrangement but I havefound it desirable to provide narrow elongatedprojections arranged in lines extending lengthwise of the blank and ofuniform height, the lines of projections being located adjacent the sideedges of the blank and also between the spaces where lines of type areto be stamped, thus providing a. line of. projections at each side ofeach line of type on the plate.

After the projections are thus formed on the blank, by any suitablestamping means and according to any suitable metal, the blank is rolledto a uniform thickness by passing it between a pair of rolls ll, 11, orin any other suitable way. The projections 10 are of uniform height onthe back of the blank regardless of the uniformity or lack of uniformityof thickness of the blank and the purpose of the rolling operation is toreduce the height of the projections where the thickness of the blankincluding the projections is greater than the predetermined standard. Ifwe assume that the thickness of the plate including the projections,that is to say between the plane of the face of the plate and the planeof the face of the projections is greater than the standard thicknessdesired, all of the projections will be reduced by the rolling operationuntil the thickness conforms with the standard; if one part. of theblank is thicker than the remainder of the blank the projections of thethick part Will be reduced more than the projections of the thin part ifthe latter are reduced at all. The projections may be completely reducedto form a smooth back for the blank, substantially as it was originally,or all of the projections may stand up more or less on the back, or theheight of the projections may vary throughout the back, these differentconditions depending upon the original thickness of the blank as will bereadily understood.

After the blank has thus been formed to a standard uniform thicknessbetween the plane of its front face and the plane of its back the typecharacters 9 are stamped up thereon between the lines of projections ina. suitable machine.

My invention provides a method and means for insuring standard uniformthickness in blanks for making printing plates and it' will be apparentthat plat-es made from blanks processed in this manner will be uniformin height and under the same conditions will give uniform impressions.

I do not limit myself to the size, shape, form, or arrangement of theprojections be cause they may be varied as desired to suit differentconditions so long as they are adapted to perform the function andproduce the result hereinbefore set forth; nor do I limit the inventionto the particular means for processing the blank in the stepshereinbefore described since it will be apparent to those skilled in theart that many different means for accomplishing these resuits may beemployed; and I reserve the right to make all changes in practicing myinvention which fairly fall within the scope of the following claims.

I claim:

1. A printing plate blank of uniform thickness and consisting of a striphaving projections on one face thereof of a height to compensate for anydeficiency in the thickness of the strip.

2. A printing plate blank of uniform thickness and consisting of a metalstrip having projections on one face thereof to make up any deficiencyin the thickness of the strip.

3. A printing plate blank of uniform thickness and consisting of a striphaving independent projections distributed over one face thereof to makeup any deficiency in the thickness of the strip.

4. A blank for a printing plate consisting of a strip having rows ofprojections on one face thereof to make up any deficiency in thethickness of the strip.

5. A printing plate blank of uniform thickness consisting of a striphaving independent projections arranged in rows on one face thereof tomake up any deficiency in the thickness of the strip.

6. A blank for a printing plate consisting of a strip having rows ofprojections located on one face thereof at opposite sides of the spacewhere the type characters are tobe stamped and of a height to compensatefor any deficiency in the thickness of the strip.

7. A blank for a printing plate consistingof a strip having rows ofprojections-located on opposite sides of each space Where typecharacters are to be stamped and of a height to compensate for anydeficiency in the thickness of the strip.

8. The herein-described method of making a blank for a printing platewhich consists in cutting a' strip to the size of the plate, stampingprojections on one face thereof,a11d then reducing said projectionswhere required to produce a blank of uniform thickness. V

9. The herein-described method of making a blank for a printing platewhich consists in cutting a strip to the size of the plate, stampingprojections on one face thereof, and then passing the blank betweenrolls to reduce said projections Where required to produce a blank ofuniform thickness.

10. The herein-described method of making a blank for a printing platewhich con sists in cutting a strip to the sizeof the plate, stampingprojections in spaced relation on' one face thereof, and then reducingsaid projections Where required to produce a blank of uniform thickness.

11. The herein-described methodof making a printing plate which consistsin cutting a strip to the size of the plate, stamping projections on oneface thereof, then reting a strip to the size of the plate, stampingducing said projections Where required to projections in rows on-onefacethereof, then I produce a blank of uniform thickness, and reducingsaid projections Where required to then stamping printing characters onthe produce a blank of uniform thickness, and

5 other face of the blank apart from said prothe'n stamping printingcharacters on the jections. other face of the blank in between the rows12. The herein-described method of makof projections.

ing a printing plate which consists in cut- JOSEPH S. DUNCAN.

